Seal



Nov. 15, 1966 N. D. TRBOVICH SEAL Filed Sept. 20, 1965 United StatesPatent 3,285,615 SEAL Nicholas D. Trbovich, 59 Fieldcrest Court, WestSeneca, N.Y. Filed Sept. 20, 1963, Ser. N0. 310,223 5 Cl aimS. (Cl.277180) This invention relates generally to the seal art, and morespecifically to a new and useful seal of a type particularly adapted foruse in place of rubber O-rings.

Metal seals possess certain advantages over rubber 0- rings, but alsopresent a problem in providing the requisite strength and rigiditywithin the limitations imposed by existing cavity diameters andpermissible flange loading. These limitations must be observed, if trueinterchangeability with rubber O-rings is desired.

Accordingly, the primary object of my invention is to provide a metallicseal of increased strength and rigidity, which seal is interchangeablewith rubber O-rings without requiring any increase in cavity diametersand while maintaining a minimum in the compression force required forsealing.

Another object of my invention is to provide a metallic seal having theaforesaid characteristics, and having improved fatigue life and pressurecapability.

Still another object of my invention is to provide the foregoing in aseal characterized by ease of manufacture.

In one aspect thereof, a seal constructed in accordance with myinvention is characterized by the provision of a member of generallyU-shaped transverse section having a base, side walls extending from thebase, and laterally outwardly projecting flanges adjacent the outer endsof the side walls, the side walls tapering toward the flanges and theflanges projecting from the outer ends of the side walls a distancegreater than the thickness of the side walls adjacent the flanges, theouter ends of the flanges being flat and providing surface engagingsea-ling areas.

In another aspect thereof, a seal constructed in accordance with myinvention is characterized by the provision of a member of generallyU-shaped transverse section having a base, side walls extending from thebase, and laterally projecting flanges adjacent the outer ends of theside walls, the side walls tapering toward the flanges, and the flangeshaving flat surface engaging outer end portions which are substantiallyparallel when the member is unstressed.

In still another aspect thereof, a seal constructed in accordance withmy invention is characterized by the provision of a member of generallyU-shaped transverse section having a base, side walls extending from thebase, and laterally projecting flanges adjacent the outer ends of theside walls, the inner surfaces of the side walls being substantiallyparallel when the member is unstressed, and the outer surfaces of theside walls converging toward the flanges.

The foregoing and other objects, advantages and characterizing featuresof my invention will becomeclearly apparent from the ensuing detaileddescription of an illustrative embodiment thereof, considered inconjunction with the accompanying drawing depicting the same, whereinlike reference numerals denote like parts throughout and wherein:

FIG. 1 is a fragmentary, longitudinal sectional view of a jointincorporating a seal of my invention; and

FIG. 2 is a view, on an enlarged scale, showing the transverse sectionalconfiguration of the seal.

Referring now in detail to the illustrative embodiment depicted in theaccompanying drawing, there is shown a seal of my invention, generallydesignated 1, positioned in the cavity 2 of a tubular member 3, to whichan end flange 4 is secured, as by bolts 5. Seal 1 is shown in itsinstalled, stressed condition in FIG. 1, while FIG. 2 shows thetransverse sectional configuration thereof in its unstressed condition.

Seal 1 is of generally U-shaped transverse section, having a base 6 andside Walls 7 extending from one side of the base. Side walls 7terminate, at their outer ends, in laterally outwardly projectingflanges 8 having flat outer ends 9 comprising the surface engagingsealing portions of the seal. That is, end surfaces 9 and particularlyedges 9A thereof are in sealing engagement with the adjacent surfaces ofmembers 3 and end flange 4. The sealing surfaces 9 and 9A are usuallycoated or plated with a ductile material 9B which will cold flow whenthe seal is compressed. This further enhances the sealing ability of theseal.

The opposite ends of base 6 are flat, as shown at 10, from the outerside 11 of base 6 to a point short of the inner side 12 thereof. Endsurfaces 10 are parallel, and act as mechanical stops preventingovercompression of seal 1, as clearly illustrated in FIG. 1.

In the unstressed condition of the seal, the inner surfaces 13 of sidewalls 7 are substantially parallel. The outer side surfaces 14 thereofare flat, like inner surfaces 13, but converge from the base endportions 10 to flanges 8. This provides side walls 7 of tapered form,the degree of taper being such that the thickness of side walls 7adjacent flanges 8 at the outer ends of the side walls is less than halfthe thickness of the side walls adjacent base 6.

This tapered side wall configuration tends to equalize stressdistribution throughout the seal, and avoids stress concentrations toprovide better fatigue life and pressure capability. Further, thematerial of the seal member is concentrated at the base 6, producing astronger seal without increasing cavity size such as would be requiredif an attempt were made to strengthen the seal by increasing its sizethroughout. This design also provides a seal of increased rigidity,without a corresponding increase in the compression force required toeffect the seal.

The provision of initially substantially parallel inner wall surfaces 13facilitates the manufacture of a tapered wall seal, with its advantages,by avoiding the problems introduced by the critical nature of aninternal taper. It also facilitates varying the thickness of base 6, andconsequently the hoop strength of the seal, without affecting either thetaper or the outer end wall form of the seal.

Flanges 8 project outwardly beyond the base end portions 10, in theunstressed condition of the seal, as clearly shown in FIG. 2. Theflanges project beyond the side walls 7, at their outer ends, a distancesubstantially twice the thickness of the side walls 7 at the outer endsthereof. Further, flanges 9 are of substantially square transversesection, in the portion thereof projecting beyond the outer ends of sidewalls 7, thereby providing a sealing surface 9 of substantial area, forincreased sealing effect as contrasted with the situation which wouldprevail if flange 8 made substantially only point contact with member 3and end flange 4. The initially substantially parallel ends 9 areimportant, because as the edges 9A are compressed the material 9B iscaused to cold flow across ends 9 and into the irregularities of thesealing surfaces on members 3 and 4, as indicated in FIG. 1, to providea greater area of sealing contact and enhanced sealing effect. If theends 9 were initially tapered, the ductile material cold flowing awayfrom edges 9A would not be retained in sealing contact with members 3and 4, and its sealing elfect would tend to be lost, leavingsubstantially only knife edge contacts between the base metal of seal 1and members 3 and 4. It is contemplated that at least end portions 9, ifnot the entire seal, will have a coating 9B of malleable material suchas silver, gold, nickel, copper or Teflon, for example, which willdeform and cold flow under the pressures involved into surfaceirregularities in members 3 and 4, to increase the sealing action.

The corners between the meeting surfaces are rounded, as clearly shownin FIG. 2, except at the sealing end portions 9 of flanges 8. Also, itwill be noted that the concentration of material at base 6 is such that,not only are the walls 7 much thicker adjacent base 6 than they areadjacent flanges 8, but base 6 itself is much thicker than wall members7 at any point therealong. This provides maximum hoop strength for agiven diameter.

Accordingly, it is seen that my invention fully accomplishes itsintended objects. While I have disclosed and described in detail onlyone embodiment of my invention, that has been done by way ofillustration, it being my intention that the scope of my invention bedefined by the appended claims.

Having fully disclosed and completely described my invention, and itsmode of operation, what I claim as new is:

1. A seal comprising an annular unitary metallic member of generallyU-shaped, radially facing transverse section having a base and oppositeside walls extending from one side thereof, said side Walls terminatingat their outer ends in laterally outwardly projecting flanges, theopposite ends of said base comprising stops against overcompression ofsaid seal, the inner surfaces of said side Walls being flat andsubstantially parallel when said member is unstressed, and the outersurfaces of said walls converging toward said outer ends thereof fromsaid base, the thickness of said side walls adjacent said outer endsthereof being no more than substantially one-half the thickness thereofadjacent said base, said base being thicker than said side walls atanypoint therealong, said flanges projecting beyond said opposite ends ofsaid base and terminating in flat surface engaging sealing end portions,said surface engaging end portions being substantially parallel whensaid member is unstressed and having a coating of ductile material whichwill cold flow into irregularities of the surfaces being sealed.

2. A seal as set forth in claim 1, wherein said coating comprises amalleable metal.

3. A seal as set forth in claim 1, wherein said coating comprises amalleable non-metallic material.

4. A seal as set forth in claim 1, said opposite ends of said base beingflat and substantially parallel from the other side of said base to apoint substantially short of said one side thereof to comprise saidstops against overcompression of said seal.

5. A seal as set forth in claim 1, said opposite ends of said base beingflat and substantially parallel to comprise said stops againstovercompression of said seal, the outer surfaces of said walls beingflat and converging toward said outer ends thereof from said flat endsof said base to said flanges when said member is unstressed, theoutwardly projecting portions of said flanges being of substantiallyrectangular transverse section, and the corners between said other sideof said base and said opposite ends thereof and between said inner Wallsurfaces and said flanges being rounded.

References Cited by the Examiner UNITED STATES PATENTS OTHER REFERENCESMachine Design The Seals Book, The Pentaton Publishing Co, Jan. 19, 1961(Copy in Div. 360 (T1 246 M3) SAMUEL ROTHBERG, Primary Examiner.

EDWARD V. BENHAM, LAVERNE D. GEIGER,

Examiners. J. S. MEDNICK, Assistant Examiner.

1. A SEAL COMPRISING AN ANNULAR UNITARY METALLIC MEMBER OF GENERALLYU-SHAPED, RADIALLY FACING TRANSVERSE SECTION HAVING A BASE AND OPPOSITESIDE WALLS EXTENDING FROM ONE SIDE THEREOF, SAID SIDE WALLS TERMINATINGAT THEIR OUTER ENDS IN LATERALLY OUTWARDLY PROJECTING FLANGES, THEOPPOSITE ENDS OF SAID BASE COMPRISING STOPS AGAINST OVERCOMPRESSION OFSAID SEAL, THE INNER SURFACES OF SAID SIDE WALLS BEING FLAT ANDSUBSTANTIALLY PARALLEL WHEN SAID MEMBER IS UNSTRESSED, THE OUTERSURFACES OF SAID WALLS CONVERGING TOWARD SAID OUTER ENDS THEREOF FROMSAID BASE, THE THICKNESS OF SAID SIDE WALL ADJACENT SAID OUTER ENDSTHEREOF BEING NO MORE THAN SUBSTANTIALLY ONE-HALF THE THICKNESS THEREOFADJACENT SAID BASE, SAID BASE BEING THICKER THAN SAID SIDE WALLS AT ANYPOINT THEREALONG, SAID FLANGES PROJECTING BEYOND SAID OPPOSITE ENDS OFSAID BASE AND TERMINATING IN FLAT SURFACE ENGAGING SEALING END PORTIONS,SAID SURFACE ENGAGING END PORTIONS BEING SUBSTANTIALLY PARALLEL WHENSAID MEMBER IS UNSTRESSED AND HAVING A COATING OF DUCTILE MATERIAL WHICHWILL COLD FLOW INTO IRREGULARTIES OF THE SURFACES BEING SEALED.